Carbon Nanodots for On Demand Chemophotothermal Therapy Combination to Elicit Necroptosis: Overcoming Apoptosis Resistance in Breast Cancer Cell Lines

SIMPLE SUMMARY: Carbon nanodots (CDs) are considered a versatile family of fluorescent, near infrared (NIR) active, and bioeliminable nanoparticles. Accordingly, the CDs application in photothermal therapy and theranostics increased. Problems limiting their use arise from the heterogeneity of most CDs and the lack of exhaustive information on their nanotoxicity at cellular and molecular levels. The lack of these data is often quite dramatic and causes substantial loss of translational value. To overcome this, we developed biocompatible homogenous CDs with a well-known structure as well as efficient red fluorescence and NIR photothermal conversion. The controlled photothermal effect and the on-demand release of the irinotecan successfully kill breast cancer cell lines in absence of relevant cell stress after internalization. We believe that these results provide insights to advance the field with significant impact, paving the way for the design of effective and safe nanomedicines for precision photothermal cancer therapies. ABSTRACT: Background: Engineered luminescent carbon nanodots (CDs) are appealing nanomaterials for cancer image-guided photothermal therapy combining near infrared (NIR)–triggered hyperthermia, imaging, and drug delivery in a single platform for efficient killing of cancer cells. This approach would allow eliciting synergistic regulated cell death (RCD) routes such as necroptosis, targeting breast cancer cells refractory to apoptosis, thus overcoming drug resistance. Methods: We report the preparation of CDs bearing biotin as a targeting agent (CDs-PEG-BT), which are able to load high amounts of irinotecan (23.7%) to be released in a pulsed on-demand fashion. CDs-PEG-BT have narrow size distribution, stable red luminescence, and high photothermal conversion in the NIR region, allowing imaging of MDA-MB231 and MCF-7 cancer cells and killing them by photothermal and chemotherapeutic insults. Results: Cellular uptake, viability profiles, and RCD gene expression analyses provided insights about the observed biocompatibility of CDs-PEG-BT, indicating that necroptosis can be induced on-demand after the photothermal activation. Besides, photothermal activation of drug-loaded CDs-PEG-BT implies both necroptosis and apoptosis by the TNFα and RIPK1 pathway. Conclusions: The controlled activation of necroptosis and apoptosis by combining phototherapy and on-demand release of irinotecan is the hallmark of efficient anticancer response in refractory breast cancer cell lines in view of precision medicine applications.